1306.3861 (Amol Dighe et al.)

Non-universality of indirect CP asymmetries in $D \to ππ, KK$ decays    [PDF]

Amol Dighe, Diptimoy Ghosh, Bhavik P. Kodrani

We point out that, if the direct CP asymmetries in the $D \to \pi^+ \pi^-$ and $D \to K^+ K^-$ decays are unequal, the indirect CP asymmetries as measured in these modes are necessarily unequal. An analysis that assumes universal indirect CP asymmetry but non-universal direct CP asymmetry would therefore be inconsistent. A model-independent fit to the current data indeed favors different indirect CP asymmetries in the above two decays. This might even offer an explanation for the apparent tension between the difference CP asymmetries $\Delta A_{\rm CP}$ measured through the pion-tagged and muon-tagged data samples at the LHCb. It also implies that the measurements of $A_\Gamma$ and $y_{\rm CP}$ in the $\pi^+ \pi^-$ and $K^+ K^-$ decay modes can be different, and averaging over these two modes should be avoided. A careful reanalysis of data is needed in order to properly account for the CP violation in the $D$ meson sector.

View original: http://arxiv.org/abs/1306.3861